The present invention relates generally to apparatus for protecting an operable computer digital data storage device from damage and loss of data in a fire. More particularly, the present invention provides for the first time a compact, forced air cooled, fire resistant enclosure for an operable computer digital data storage device. Typical computer digital data storage devices include computer hard drives, optical disk drives, solid state memory devices, tape drives, computers, or any other device which can actively read and write digital data with the intent of storing and retrieving computerized digital data.
As digital data storage devices become able to store staggering amounts of data, the loss of a digital data storage device in a fire becomes more and more catastrophic. There is clearly a need to provide a compact, reliable fire resistant enclosure for operating digital data storage devices.
The prior art includes a relatively large enclosure for operable digital data storage devices, such as the Engler U.S. Pat. No. 6,158,833, which dissipates heat generated by the digital data storage device through the insulated walls of the container. The Engler design requires a relatively large enclosure since it does not provide any active or fan-driven cooling system. The present invention, in contrast, provides a compact enclosure a fraction of the size of the Engler enclosure. The compact size of the present invention is achieved primarily because of a forced-air cooling system not present in the Engler device.
The prior art includes other digital data storage device enclosures with “passive” cooling systems, such as Pihl et al U.S. Pat. No. 5,479,341 which cools by convection through a partially open vent door. This technique is “free convection” because no fan or other active device is used to cause the convection. The Kikinis U.S. Pat. No. 5,623,597 utilizes a rather complex, passive heat exchanger with a rather large heat sink structure. That design requires a cumbersome insulation injection mechanism to fill the heat sink space when a threshold temperature is sensed.
The prior art also includes the Kishon et al published U.S. application No. U.S. 2004/0064631 dated Apr. 1, 2004. The Kishon et al device utilizes passive conduction of heat generated by the data storage device through screws to the device cover (see paragraph [0021]). This technique is limited by the relatively low amount of heat transferable through the metal screws. The active, fan-driven cooling provided by the present invention achieves a much greater cooling capacity.
The prior art also includes forced air cooling systems for operational digital data storage drives, but not used together with a compact, fire resistant enclosure.
The present invention provides a compact fire resistant enclosure having one or more fire resistant movable hatches. In its open position, the movable hatch provides inlet and/or exhaust passage for ambient air. A fan driven cooling system (also referred to as “forced convection”) actively cools the digital data storage device with ambient air. As used herein and in the claims, the word “fan” and the phrase “fan means” are used broadly to include bladed fans, squirrel cage fans, blowers, impellers and other active devices used to cause forced convection currents of air. When a predetermined temperature is sensed, the movable hatch or hatches automatically close. The mechanism for closing the hatch can be, without limitation, a temperature sensitive element such as an eutectic metal, plastic, rubber, chemical, liquid, solid or wax that melts or expands at a specific temperature and causes the hatch to close. The temperature sensitive element can be used together with actuation springs that expand or contract to close the hatch. The temperature sensitive element could also support the top of the enclosure and gravity close the hatch when the element melts. Alternately, the movable hatch or vent door may be electronically closed by a solenoid wherein the solenoid is actuated by a thermocouple or other element when a specific temperature is sensed. Other electronic actuation means or other passive methods (temperature sensitive elements) may also be utilized to automatically close the hatch or vent door. Furthermore, another embodiment is to provide air inlet and exhaust ports or passageways that are automatically closed, either actively (electronic actuation) or passively (temperature sensitive elements), when a specific temperature is sensed. Another variation is to cause the top (or upper wall) of the enclosure to open and close by either being hinged along one edge, for example, or by providing a moving portion of the top (or upper wall) of the enclosure. The “temperature sensitive element” is either an eutectic metal, wax, plastic, rubber, chemical, liquid, solid, electronic sensor or electronic actuator, for example. In addition, multiple data storage devices may be “rack mounted” in a single enclosure.
In each of the embodiments described herein, a temperature sensitive element is “activated” in the presence of a threshold temperature. For example, a meltable tab is activated by melting, a solenoid coupled to a temperature sensor is activated by either extending or retracting its arm in response to the temperature sensor, and an evaporative material is activated by expanding in the presence of the threshold temperature.
A primary object of the invention is to provide a fire resistant enclosure for an operable digital data storage device having a forced air cooling system capable of cooling large capacity data storage devices.
A further object of the invention is to provide a fire resistant enclosure for an operating digital data storage device having an extremely reliable sensing and actuation system with minimum moving parts.
A further object of the invention is to provide a fire resistant enclosure for an operable digital data storage device which substantially reduces or eliminates false alarms and the associated damage and mess created by prior art systems in the event of a false alarm.
Still another object of the invention is to provide a fire resistant enclosure for one or more operating computer digital data storage devices, which is relatively small in size while simultaneously having a large capacity for cooling the data storage device.
Other objects and advantages of the invention will become apparent from the following description and the drawings wherein: